Manufacture of polyhydroxy anthraquinone sulfonic acids



Patented Nov. 13, 1951 Curt Bamberger, Jersey CitymndJohn FVJQreInp,:Short Hills, N. J assignorsto ratentflhemic'als. :Incorporated,Paterson, NFL, 'a. corporation of New Jersey No Drawing. liplmamnaioeibmiai1e48,

' Serial No. 53,753

"is-claims. (ct-260L375)- This invention relates to a process for themann-facture of polyhydroxy-anthraquinone.sulfonic acids and especiallyIA-dihydrOXy-anthraquinone sulfonic acids.

- The technically valuable lA-dihydroxy an- ;thraquinone-z-sulfonic.acidseof the. .g'enerallfor- -'mu1a wherein X, Y, Z stands for hydrogenor any sub- -Stitll&llt such as halo'gen,-thesulfonic-acid group,

the hydroxy group, or othersareobtainable according to theprocess-ofGerman. Patent 287,867 by reacting 1.4 dihydroxy anthraquinone of thegeneral-formula:

..z 0 on in aqueous medium" with sulfita preferably in the-presence ofmanganese dioxide.

We have now found that by using organic intro-compounds instead of metalioxidesias mananese dioxide,- amuch. improved :processlistobtained.

Using certain organic nitro-com'pounds, especially water soluble organicnitro-compounds, the conversion of 1.4-dihydroxy-anthraquinone into the2-sulfonic acid is complete in l to 2 hours heating in an open vessel.This represents an important technical advantage not only in shorteningthe time required, but also in avoidance of the troublesome separationof the reaction product from water soluble manganese or other metallicsalts as for example cupric salts.

Moreover, according to the procedure of the German patent, the reactionproduct has to be separated from unreacted material. Because of completeconversion of lA-dihydroxy-anthraquinone according to the presentinvention, this separation step is unnecessary.

The present invention comprises reacting 1.4- dihydroxy-anthraquinonewith a sulfite in water in the presence of an organic nitro-compound,preferably water soluble, at elevated temperature until a test showsthat all the 1.4-dihydroxy-anthraquinone has become water soluble.

. 52 vThe.ffollovving specific examples" will [further illustrate' the.invention, but it, is.'understood that jthelinvention notffliniitedthereto. The parts are"by'wight. Example 1 24 lbs. of sifted 1.4'dihydroxy-anthraquinone 20 lbs. ofm-nitrobenzene=sulfonic=:acida.(sodium salt) 1 750 lbs. of water.

are I heated withvigorous" stirring to C. and "kept between-'95" C; and-C. After! 5:minutes on temperature, 5 lbs. of sodium bicarbonateuisadde'd andia'fter :a -further 10 minutes; 5" lbs; more :-1'-"-"sodiumbicarbonate ':is: added forlthea purpose or reducing the alkalinity:ofxthe mixture. --'A *'sample taken iafterxabout 2i'hours,': dilutedwith water and acidi'fied, 'shows'rthati 2.11.1 .4-idi-'hydroxy-anthraquinone. has ibecomawaterisolu- :ble. Thereactionzproductseparates"asfa reddish maroonprecipitate.

T Ihe i reaction mixture is then .cooled, :made strongly acid, whereuponthe 11".4-.dihydroxy= an- "thraquinone'z sulfonic acid .or its .5 sodiumsalt separates bright 'orange' crystals, whichxare collected' on -afilter; washed with brinezand dried.

' "Example 2' v .24I1bs. ofcsifted l A-dihydroxy-anthraquinone 800lbs-of waterareheated withlgood agitation to :95.C.

are added, whereupon the reaction starts immediately. After 5 minutes atabout 95-100 0., 5 lbs. of sodium bicarbonate is added. After a further10 minutes, 5 lbs. more of sodium bicarbonate is added.

After about 2 hours at 95-100 C. an acidified sample shows that alllA-dihydroxy-anthr'aquinone is converted into the water solublesulfoacid. After the sulfonation is finished, the excess of nitrobenzeneis boiled ofi, the mass cooled to about 60 C. and made strongly acid.

The 1.4' dihydroxy-anthraquinone-2-sulfonic acid separates incrystallized form and is collected on a filter, washed neutral withbrine and dried.

It is thus possible to use a non-soluble oxidizing agent such asnitrobenzene but because the water soluble compounds are present insolution and the excess thereof may be separated by filtration ratherthan by distillation, they are preferred. Furthermore, the fumes ofnitrobenzene are toxic.

3 Example 3 lbs. of 1.4.5.6 tetra-hydroxy-anthraquinone 20 lbs. ofsodium sulflte 300 lbs. of water are heated with vigorous agitation to95-100 C.

whereupon 12 lbs. of m-nitrobenzene-sulfo-acid are added. Thetemperature is then kept between 97 and 100 C.

The reaction mixture becomes more blue. After one-half hour, 3 lbs. ofsodium bicarand more bonate are added and after another one half hour, 3lbs. more of sodium bicarbonate are added.

After four hours on temperature, the reaction ample 1.

The reaction product separates from its clear The reaction mixture iscooled and poured into .35

an excess of dilute sulfuric acid. After filtering from unreactedstarting material, the reaction product is isolated from the filtrateby-salting with 15% salt while hot, and then coolingto 50 C. Thereaction product separates in the form of fine brown particles, whichare filtered ofi, washed with 15% brine and dried; ;The product,precipitated in the usual way with aluminum hydroxide gives a brightblue lake. I

Instead of 1.1-dihydroxy-anthraquinone, substituted1.4-dihydrcxy-anthraquinone may be used, containing one ormoresubstituents in the 5, 6, 7 or 8 position.fi-chloro-1.4-dihydroxy-anthraquinone for instance, treated according toExample 1 gives a fi-chloro-lA-dihydroxy-anthraquinone-2-(or 3)-sulfonicacid and 1.4-dihydroxy-anthraquinone-G-sulfo-acid g ves the1A-dihydroxy-anthraquinone-2.6-disulfo-acid.

Instead of nitrobenzene-sulfonic acid other or- 15 mixture is cooled andworked up'similar to'liix-v 4 ganic nitro-compounds can be used, forinstance. nitro-toluene-sulfonic acid, nitro-naphthalene sulfonic acid,nitrotoluene and many others.

We claim:

I 1. The "process of preparing IA-dihydroxyanthraquinone-sulfo-acids byreacting in aqueous solution in the temperature range C. to 0., sodiumsulfite, a nitro-compound of the series, benzol, naphthalene, and a1,4-dihydroxy-anthraquinone of the following general formula:

. wherein each of X, Y, Z occupies one of the following four ringpositions: 5, 6, '7 and 8, and stands for one of the group: hydroxy,halogen. sulfo.

2. The process according to claim 1 in which the nitro-compound innitrobenzene-sulfonic acid.

3. The process of preparing 1,4-dihydroxyanthraquinone-Z-sulfonicacidwhich consists in reacting in the temperature range 75 C. to 110 C.1,4-dihydroxy-anthraquinone with an aqueous solution of sodium sulfitein the presence of a nitro-compound of the series: benzol, naphthalene.

CURT BAMBERGER. JOHN W. ORELUP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Lassar-Cohn: Arbeitsmethoden fur Organisch,Chemische Laboratorien, Funte Aufiage, Spezieller Teil (1923) pages735-36.

1. THE PROCESS OF PREPARING 1,4-DIHYDROXYANTHRAQUINONE-SULFO-ACIDS BYREACTING IN AQUEOUS SOLUTION IN THE TEMPEATURE RANGE 75* C. TO 110* C.,SODIUM SULFITE, A NITRO-COMPOUND OF THE SERIES BENZOL, NAPHTHALENE, ANDA 1,4-DIHYDROXY-ANTHRAQUINONE OF THE FOLLOWING GENERAL FORMULA: